Large storage tanks are used to store a variety of liquids, including petroleum, and various petroleum products. Commonly these tanks are subject to corrosion and eventual failure over time. Particulate and sediment will almost always be present in such storage tanks necessitating frequent inspections to ensure quality of the product stored in the tank. Such regular inspections can be expensive and inconvenient, especially if it is necessary to empty a tank each time it is to be inspected. Also complicating the inspection process is the concern for the safety of the inspector.
Older systems for measuring basic particulate and water contamination are time consuming and inaccurate. One system includes the steps of removing a sample, heating the sample and centrifuging the sample to separate particulate, water and petroleum products. This system requires too much handling and processing and usually involves the shipment of samples to a lab for analysis.
More recent systems for monitoring particulate matter require complicated, expensive equipment. One system uses a back scattered laser with detection optics. Another system for in situ measurement of corrosion in filled tanks uses ultrasonic pulses with an ultrasonic transducer in combination with a remote, automated device inside the tank. Another system for in-line particulate monitoring uses a controller with a series of in-line accumulators and sampling units.
A need exists for a simple, reliable tank inspection and sampling program.